Why is gold is valuable?

Gold is valuable because people THINK it's valuable. It's pretty, and sort-of rare, and people have always thought that gold was valuable, so people STILL think it is valuable.

Gold is useful for jewelry, and it has some nice engineering applications. But the reason it is valuable is because it is valuable.

Sort of like Paris Hilton was famous for being famous, not because she had actually DONE anything worthy of fame.